! Perinatal depression and anxiety are common, serious, and frequently overlapping disorders that increase morbidity and mortality in new mothers (including suicide) and result in poor infant/child outcomes. Current therapies often fail to produce recovery or are poorly tolerated, and many pregnant women seek non- pharmacologic therapy or forgo treatment when non-pharmacologic options are not available. Expectant and new mothers who experience circadian rhythm dysregulation are at increased risk for perinatal depression. This Confirmatory Efficacy Clinical Trial of Non-Pharmacological Interventions for Mental Disorders R01 seeks to test whether a Personalized Integrated Chronotherapy (PIC) intervention can improve treatment outcomes for pregnant patients seeking outpatient treatment for depression, with or without anxiety. PIC is a multicompo- nent treatment consisting of bright light therapy, sleep phase advance, and sleep stabilization/restriction that targets the Research Domain Criteria (RDoC) constructs of circadian rhythms and sleep-wake behavior. To increase sample size and diversity and accelerate recruitment, this study will be performed at 4 sites that differ in clinical structure and that have piloted the PIC intervention. The study will enroll expectant mothers diag- nosed with major depressive disorder during 3rd trimester of pregnancy. We will randomize patients to either: (a) usual care (UC, n = 110) or (b) PIC+UC (n = 110). PIC+UC will have pregnancy and postpartum compo- nents and will be administered via a personalized approach tailored to optimize the intervention based on each patient?s individual circadian and sleep timing. After a baseline assessment, PIC will be prescribed during 5 dedicated clinical visits: three during 3rd trimester of pregnancy and 2 in the postpartum period. UC will consist of medication and/or psychotherapy. UC will be quantified in both groups to evaluate differences between the PIC+UC and UC groups. Mood will be measured in both groups by blinded clinician interview and patient self- report. The safety profile of the PIC intervention will be assessed by evaluation of side effects/adverse events. Importantly, the study will also examine the target mechanisms by which PIC is hypothesized to work and test the mediation effects of the circadian targets on improvement in mood symptoms. Participants will wear wrist actigraphy/light monitors continuously during weeks 28-40 of pregnancy and postpartum weeks 2-6 to assess light exposure and to estimate sleep timing and duration. Circadian phase (measured with salivary dim light melatonin onset) will be measured at baseline during pregnancy (~30 weeks? gestation), at 36 weeks? gestation, and at postpartum week 6. Exploratory aims will examine associations between infant sleep behavior and ma- ternal circadian rhythms and factors relevant to future dissemination of PIC. If this intervention is effective, per- inatal PIC could change clinical practice and have major public health impact due to the high prevalence of perinatal depression and anxiety, the negative effects of mood disorders on mothers and their children, and the need to provide effective, novel, non-pharmacologic therapies for women with perinatal mood disorders. !